Designation D323 − 15a Standard Test Method for Vapor Pressure of Petroleum Products (Reid Method)1 This standard is issued under the fixed designation D323; the number immediately following the desig[.]
Trang 1Designation: D323−15a
Standard Test Method for
This standard is issued under the fixed designation D323; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision A number in parentheses indicates the year of last reapproval A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S Department of Defense.
1 Scope*
1.1 This test method covers procedures for the
determina-tion of vapor pressure (seeNote 1) of gasoline, volatile crude
oil, and other volatile petroleum products
1.2 Procedure A is applicable to gasoline and other
petro-leum products with a vapor pressure of less than 180 kPa
(26 psi)
1.3 Procedure B may also be applicable to these other
materials, but only gasoline was included in the interlaboratory
test program to determine the precision of this test method
1.4 Procedure C is for materials with a vapor pressure of
greater than 180 kPa (26 psi)
1.5 Procedure D for aviation gasoline with a vapor pressure
of approximately 50 kPa (7 psi)
NOTE 1—Because the external atmospheric pressure is counteracted by
the atmospheric pressure initially present in the vapor chamber, the Reid
vapor pressure is an absolute pressure at 37.8 °C (100 °F) in kilopascals
(pounds-force per square inch) The Reid vapor pressure differs from the
true vapor pressure of the sample due to some small sample vaporization
and the presence of water vapor and air in the confined space.
1.6 This test method is not applicable to liquefied petroleum
gases or fuels containing oxygenated compounds other than
methyl t-butyl ether (MTBE) For determination of the vapor
pressure of liquefied petroleum gases, refer to Test Method
D1267or Test MethodD6897 For determination of the vapor
pressure of gasoline-oxygenate blends, refer to Test Method
D4953 The precision for crude oil has not been determined
since the early 1950s (see Note 3) Test Method D6377 has
been approved as a method for determination of vapor pressure
of crude oil IP 481 is a test method for determination of the
air-saturated vapor pressure of crude oil
1.7 The values stated in SI units are to be regarded as the
standard The values given in parentheses are for information
only
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use Specific warning
statements are given in Sections 7 and18, and 12.5.3, 15.5, 21.2,A1.1.2,A1.1.6, andA2.3
2 Referenced Documents
2.1 ASTM Standards:2
D1267Test Method for Gage Vapor Pressure of Liquefied Petroleum (LP) Gases (LP-Gas Method)
D4057Practice for Manual Sampling of Petroleum and Petroleum Products
D4175Terminology Relating to Petroleum, Petroleum Products, and Lubricants
D4953Test Method for Vapor Pressure of Gasoline and Gasoline-Oxygenate Blends (Dry Method)
D6377Test Method for Determination of Vapor Pressure of Crude Oil: VPCRx(Expansion Method)
D6897Test Method for Vapor Pressure of Liquefied Petro-leum Gases (LPG) (Expansion Method)
E1Specification for ASTM Liquid-in-Glass Thermometers E2251Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids
2.2 Energy Institute Standards:
IP 481Test Method for Determination of the Air Saturated Vapour Pressure (ASVP) of Crude Oil3
3 Terminology
3.1 Definitions:
3.1.1 Bourdon spring gauge, n—pressure measuring device
that employs a Bourdon tube connected to an indicator
3.1.2 Bourdon tube, n—flattened metal tube bent to a curve
that straightens under internal pressure
1 This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.08 on Volatility.
Current edition approved June 1, 2015 Published June 2015 Originally
approved in 1930 Last previous edition approved in 2015 as D323 – 15 DOI:
10.1520/D0323-15A.
2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR, U.K., http://www.energyinst.org.uk.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959 United States
Trang 23.1.3 oxygenate, n—oxygen-containing ashless organic
compound, such as an alcohol or ether, which may be used as
3.1.4 Reid vapor pressure (RVP), n—resultant total pressure
reading, corrected for measuring error, of a specific empirical
test method (Test Method D323) for measuring the vapor
pressure of gasoline and other volatile products
3.1.5 vapor pressure, n—pressure exerted by the vapor of a
liquid when in equilibrium with the liquid D4175
3.2 Abbreviations:
3.2.1 ASVP, n—air saturated vapor pressure.
3.2.2 LPG, n—liquefied petroleum gases.
3.2.3 MTBE, n—methyl t-butyl ether.
3.2.4 RVP, n—Reid Vapor Pressure.
4 Summary of Test Method
4.1 The liquid chamber of the vapor pressure apparatus is
filled with the chilled sample and connected to the vapor
chamber that has been heated to 37.8 °C (100 °F) in a bath The
assembled apparatus is immersed in a bath at 37.8 °C (100 °F)
until a constant pressure is observed The reading, suitably
corrected, is reported as the Reid vapor pressure
4.2 All four procedures utilize liquid and vapor chambers of
the same internal volume Procedure B utilizes a
semiauto-matic apparatus immersed in a horizontal bath and rotated
while attaining equilibrium Either a Bourdon gauge or
pres-sure transducer may be used with this procedure Procedure C
utilizes a liquid chamber with two valved openings Procedure
D requires more stringent limits on the ratio of the liquid and
vapor chambers
5 Significance and Use
5.1 Vapor pressure is an important physical property of
volatile liquids This test method is used to determine the vapor
pressure at 37.8 °C (100 °F) of petroleum products and crude
oils with initial boiling point above 0 °C (32 °F)
5.2 Vapor pressure is critically important for both
automo-tive and aviation gasolines, affecting starting, warm-up, and
tendency to vapor lock with high operating temperatures or
high altitudes Maximum vapor pressure limits for gasoline are
legally mandated in some areas as a measure of air pollution
control
5.3 Vapor pressure of crude oils is of importance to the
crude producer and the refiner for general handling and initial
refinery treatment
5.4 Vapor pressure is also used as an indirect measure of the
evaporation rate of volatile petroleum solvents
6 Apparatus
6.1 The required apparatus for Procedures A, C, and D is
described inAnnex A1 Apparatus for Procedure B is described
inAnnex A2
7 Hazards
7.1 Gross errors can be obtained in vapor pressure
measure-ments if the prescribed procedure is not followed carefully The
following list emphasizes the importance of strict adherence to the precautions given in the procedure:
7.1.1 Checking the Pressure Gauge—Check all gauges
against a pressure measuring device (seeA1.6) after each test
to ensure higher precision of results (see12.4) Read the gauge while in a vertical position and after tapping it lightly
7.1.2 Checking for Leaks—Check all apparatus before and
during each test for both liquid and vapor leaks (seeNote 5)
7.1.3 Sampling—Because initial sampling and the handling
of samples will greatly affect the final results, employ the utmost precaution and the most meticulous care to avoid losses through evaporation and even slight changes in composition (see Section8and12.1) In no case shall any part of the Reid apparatus itself be used as the sample container prior to actually conducting the test
7.1.4 Purging the Apparatus—Thoroughly purge the
pres-sure gauge, the liquid chamber, and the vapor chamber to be sure that they are free of residual sample This is most conveniently done at the end of the test in preparation for the next test (see12.5and15.5)
7.1.5 Coupling the Apparatus—Carefully observe the
re-quirements of12.2
7.1.6 Shaking the Apparatus—Shake the apparatus
vigor-ously as directed to ensure equilibrium
8 Sampling
8.1 The extreme sensitivity of vapor pressure measurements
to losses through evaporation and the resulting changes in composition is such as to require the utmost precaution and the most meticulous care in the handling of samples The provi-sions of this section shall apply to all samples for vapor pressure determinations, except as specifically excluded for samples having vapor pressures above 180 kPa (26 psi); see Section19
8.2 Sampling shall be done in accordance with Practice D4057
8.3 Sample Container Size—The size of the sample
con-tainer from which the vapor pressure sample is taken shall be
1 L (1 qt) It shall be 70 % to 80 % filled with sample 8.3.1 The present precision statement has been derived using samples in 1 L (1 qt) containers However, samples taken
in containers of other sizes as prescribed in PracticeD4057can
be used if it is recognized that the precision could be affected
In the case of referee testing, the 1 L (1 qt) sample container shall be mandatory
8.4 The Reid vapor pressure determination shall be per-formed on the first test specimen withdrawn from the sample container The remaining sample in the container cannot be used for a second vapor pressure determination If necessary, obtain a new sample
8.4.1 Protect samples from excessive heat prior to testing 8.4.2 Do not test samples in leaky containers They should
be discarded and new samples obtained
8.5 Sampling Handling Temperature—In all cases, cool the
sample container and contents to 0 °C to 1 °C (32 °F to 34 °F) before the container is opened Sufficient time to reach this temperature shall be ensured by direct measurement of the
Trang 3temperature of a similar liquid in a like container placed in the
cooling bath at the same time as the sample
9 Report
9.1 Report the result observed in12.4or15.4, after
correct-ing for any difference between the gauge and the pressure
measuring device (seeA1.6), to the nearest 0.25 kPa (0.05 psi)
as the Reid vapor pressure
10 Precison and Bias
10.1 The following criteria are to be used for judging the
acceptability of results (95 % confidence):
10.1.1 Repeatability—The difference between successive
test results obtained by the same operator with the same
apparatus under constant operating conditions on identical test
material would, in the long run, in the normal and correct
operation of the test method, exceed the following value only
in one case in twenty
Range Repeatability
D Aviation
10.1.2 Reproducibility—The difference between two, single
and independent results, obtained by different operators
work-ing in different laboratories on identical test material would, in
the long run, in the normal and correct operation of the test
method, exceed the following value only in one case in twenty
Range Reproducibility
D Aviation
NOTE 2—These precision values are derived from a 1987 cooperative
program 4 and the current Committee D02 Statistical Method
RR:D02-1007.
NOTE 3—These precision values were developed in the early 1950’s,
prior to the current statistical evaluation method.
10.2 Bias:
10.2.1 Absolute Bias—Since there is no accepted reference
material suitable for determining the bias for this test method,
bias cannot be determined The amount of bias between this
test vapor pressure and true vapor pressure is unknown
10.2.2 Relative Bias—There is no statistically significant
bias between Procedures A and B for gasolines as determined
in the last cooperative test program
PROCEDURE A FOR PETROLEUM PRODUCTS HAVING REID VAPOR PRESSURES BELOW 180 kPa (26 psi)
11 Preparation for Test
11.1 Verification of Sample Container Filling—With the
sample at a temperature of 0 °C to 1°C, take the container from the cooling bath or refrigerator and wipe dry with absorbent material If the container is not transparent, unseal it, and using
a suitable gauge, confirm that the sample volume equals 70 %
to 80 % of the container capacity (seeNote 4) If the sample is contained in a transparent glass container, verify that the container is 70 % to 80 % full by suitable means (seeNote 4)
NOTE 4—For nontransparent containers, one way to confirm that the sample volume equals 70 % to 80 % of the container capacity is to use a dipstick that has been pre-marked to indicate the 70 % and 80 % container capacities The dipstick should be of such material that it shows wetting after being immersed and withdrawn from the sample To confirm the sample volume, insert the dipstick into the sample container so that it touches the bottom of the container at a perpendicular angle, before removing the dipstick For transparent containers, using a marked ruler or
by comparing the sample container to a like container that has the 70 % and 80 % levels clearly marked, has been found suitable.
11.1.1 Discard the sample if its volume is less than 70 % of the container capacity
11.1.2 If the container is more than 80 % full, pour out enough sample to bring the container contents within the 70 %
to 80 % range Under no circumstances shall any sample poured out be returned to the container
11.1.3 Reseal the container, if necessary, and return the sample container to the cooling bath
11.2 Air Saturation of Sample in Sample Container: 11.2.1 Nontransparent Containers—With the sample again
at a temperature between 0 °C and 1 °C, take the container from the cooling bath, wipe it dry with an absorbent material, remove the cap momentarily taking care that no water enters, reseal, and shake vigorously Return it to the cooling bath for
a minimum of 2 min
11.2.2 Transparent Containers—Since11.1does not require that the sample container be opened to verify the sample capacity, it is necessary to unseal the cap momentarily before resealing it so that samples in transparent containers are treated the same as samples in nontransparent containers After per-forming this task, proceed with11.2.1
11.2.3 Repeat11.2.1twice more Return the sample to the bath until the beginning of the procedure
11.3 Preparation of Liquid Chamber—Completely immerse
the open liquid chamber in an upright position and the sample transfer connection (seeFig A1.2) in a bath at a temperature between 0 °C and 1 °C (32 °F and 34 °F) for at least 10 min
11.4 Preparation of Vapor Chamber—After purging and
rinsing the vapor chamber and pressure gauge in accordance with 12.5, connect the gauge to the vapor chamber Immerse
4 Supporting data have been filed at ASTM International Headquarters and may
be obtained by requesting Research Report RR:D02-1245.
Trang 4the vapor chamber to at least 25.4 mm (1 in.) above its top in
the water bath maintained at 37.8 °C 6 0.1 °C (100 °F 6
0.2 °F) for not less than 10 min just prior to coupling it to the
liquid chamber Do not remove the vapor chamber from the
bath until the liquid chamber has been filled with sample, as
described in12.1
12 Procedure
12.1 Sample Transfer—Remove the sample from the
cool-ing bath, uncap, and insert the chilled transfer tube (seeFig 1)
Remove the liquid chamber from the cooling bath, and place
the chamber in an inverted position over the top of the transfer
tube Invert the entire system rapidly so that the liquid chamber
is upright with the end of the transfer tube approximately 6 mm
(0.25 in.) from the bottom of the liquid chamber Fill the
chamber to overflowing (in addition to other precautions, make
provision for suitable containment and disposal of the
over-flowing sample to avoid fire hazard) Withdraw the transfer
tube from the liquid chamber while allowing the sample to
continue flowing up to complete withdrawal
12.2 Assembly of Apparatus—Immediately remove the
va-por chamber from the water bath and couple the filled liquid
chamber to the vapor chamber as quickly as possible without
spillage When the vapor chamber is removed from the water
bath, connect it to the liquid chamber without undue movement
that could promote exchange of room temperature air with the
37.8 °C (100 °F) air in the chamber Not more than 10 s shall
elapse between removing the vapor chamber from the water
bath and completion of the coupling of the two chambers
12.3 Introduction of the Apparatus into Bath—Turn the
assembled apparatus upside down and allow all the sample in
the liquid chamber to drain into the vapor chamber With the
apparatus still inverted, shake it vigorously eight times up and
down With the gauge end up, immerse the assembled
appara-tus in the bath, maintained at 37.8 °C 6 0.1 °C (100 °F 6
0.2 °F), in an inclined position so that the connection of the
liquid and vapor chambers is below the water level and
carefully examine for leaks (see Note 5) If no leaks are
observed, further immerse the apparatus to at least 25 mm
(1 in.) above the top of the vapor chamber Observe the
apparatus for leaks throughout the test and discard the test at
anytime a leak is detected
NOTE 5—Liquid leaks are more difficult to detect than vapor leaks Pay particular attention to the coupling between the chambers, which is normally in the liquid section of the apparatus.
12.4 Measurement of Vapor Pressure—After the assembled
apparatus has been in the water bath for at least 5 min, tap the pressure gauge lightly and observe the reading Withdraw the apparatus from the bath and repeat the instructions of12.3 At intervals of not less than 2 min, tap the gauge, observe the reading, and repeat 12.3 until a total of not less than five shakings and gauge readings have been made Continue this procedure, as necessary, until the last two consecutive gauge readings are the same, indicating that equilibrium has been attained Read the final gauge pressure to the nearest 0.25 kPa (0.05 psi) and record this value as the uncorrected vapor pressure of the sample Without undue delay, remove the pressure gauge from the apparatus (see Note 6) without attempting to remove any liquid that may be trapped in the gauge, check its reading against that of the pressure measuring device (seeA1.6) while both are subjected to a common steady pressure that is within 1.0 kPa (0.2 psi) of the recorded uncorrected vapor pressure If a difference is observed between the pressure measuring device and the pressure gauge readings, the difference is added to the uncorrected vapor pressure when the pressure measuring device reading is higher, or subtracted from the uncorrected vapor pressure when the pressure mea-suring device reading is lower, and the resulting value recorded
as the Reid vapor pressure of the sample
NOTE 6—Cooling the assembly prior to disconnecting the gauge will facilitate disassembly and reduce the amount of hydrocarbon vapors released into the room.
12.5 Preparation of Apparatus for Next Test:
12.5.1 Thoroughly purge the vapor chamber of residual sample by filling it with warm water above 32 °C (90 °F) and allowing it to drain Repeat this purging at least five times Purge the liquid chamber in the same manner Rinse both chambers and the transfer tube several times with petroleum naphtha, then several times with acetone, then blow dry using dried air Place the liquid chamber in the cooling bath or refrigerator in preparation for the next test
12.5.2 If the purging of the vapor chamber is done in a bath,
be sure to avoid small films of floating sample by keeping the bottom and top openings of the chamber closed as they pass through the water surface
12.5.3 Preparation of Gauge—Disconnect the gauge from
its manifold connection with the pressure measuring device and remove trapped liquid in the Bourdon tube of the gauge by repeated centrifugal thrusts This is accomplished in the following manner: hold the gauge between the palms of the hands with the right palm on the face of the gauge and the threaded connection of the gauge forward Extend the arms forward and upward at an angle of 45° Swing the arms rapidly downward through an arc of about 135° so that centrifugal force aids gravity in removing trapped liquid Repeat this operation at least three times or until all liquid has been expelled from the gauge Connect the gauge to the vapor chamber with the liquid connection closed and place in the 37.8 °C (100 °F) bath to condition for the next test
(Warning—Do not leave the vapor chamber with the gauge
FIG 1 Simplified Sketches Outlining Method Transferring
Sample to Liquid Chamber from Open-Type Containers
Trang 5attached in the water bath for a longer period of time than
necessary to condition for the next test Water vapor can
condense in the Bourdon tube and lead to erroneous results.)
PROCEDURE B FOR PETROLEUM PRODUCTS HAVING REID
VAPOR PRESSURES BELOW 180 kPa (26 psi),
(HORIZONTAL BATH)
13 Sampling
13.1 Refer to Section8
14 Preparation for Test
14.1 Refer to Section11
15 Procedure
15.1 Sample Transfer— Remove the sample from the
cool-ing bath, uncap, and insert the chilled transfer tube (seeFig 1)
Remove the liquid chamber from the cooling bath, and place
the chamber in an inverted position over the top of the transfer
tube Invert the entire system rapidly so that the liquid chamber
is upright with the end of the transfer tube approximately 6 mm
(0.25 in.) from the bottom of the liquid chamber Fill the
chamber to overflowing (in addition to other precautions, make
provision for suitable containment and disposal of the
over-flowing sample to avoid fire hazard) Withdraw the transfer
tube from the liquid chamber while allowing the sample to
continue flowing up to complete withdrawal
15.2 Assembly of Apparatus—Immediately remove the
va-por chamber from the water bath Disconnect the spiral tubing
at the quick action disconnect Couple the filled liquid chamber
to the vapor chamber as quickly as possible without spillage or
movement that could promote exchange of room temperature
air with the 37.8 °C (100 °F) air in the vapor chamber Not
more than 10 s shall elapse between removing the vapor
chamber from the water bath and completion of the coupling of
the two chambers
15.3 Introduction of the Apparatus into the Bath—While
holding the apparatus vertically, immediately reconnect the
spiral tubing at the quick action disconnect Tilt the apparatus
between 20° and 30° downward for 4 s or 5 s to allow the
sample to flow into the vapor chamber without getting into the
tube extending into the vapor chamber from the gauge, or
pressure transducer Place the assembled apparatus into the
water bath maintained at 37.8 °C 6 0.1 °C (100 °F 6 0.2 °F)
in such a way that the bottom of the liquid chamber engages the
drive coupling and the other end of the apparatus rests on the
support bearing Turn on the switch to begin the rotation of the
assembled liquid-vapor chambers Observe the apparatus for
leakage throughout the test (see Note 5) Discard the test at
anytime a leak is detected
15.4 Measurement of Vapor Pressure—After the assembled
apparatus has been in the bath for at least 5 min, tap the
pressure gauge lightly and observe the reading Repeat the
tapping and reading at intervals of not less than 2 min, until
two consecutive readings are the same (Tapping is not
necessary with the transducer model but the reading intervals
should be the same.) Read the final gauge or transducer pressure to the nearest 0.25 kPa (0.05 psi) and record this value
as the uncorrected vapor pressure Without undue delay, disconnect the gauge from the apparatus Connect the gauge or pressure transducer to a pressure measuring device Check its reading against that of the pressure measuring device while both are subjected to a common steady pressure that is within 1.0 kPa (0.2 psi) of the recorded uncorrected vapor pressure If
a difference is observed between the pressure measuring device and gauge or transducer readings, the difference is added to the uncorrected vapor pressure when the pressure measuring device reading is higher, or subtracted from the uncorrected vapor pressure when the pressure measuring device reading is lower, and the resulting value recorded as the Reid vapor pressure of the sample
15.5 Preparation of Apparatus for Next Test:
15.5.1 Thoroughly purge the vapor chamber of residual sample by filling it with warm water above 32 °C (90 °F) and allowing it to drain Repeat this purging at least five times Purge the liquid chamber in the same manner Rinse both chambers and the transfer tube several times with petroleum naphtha, then several times with acetone, then blow dry using dried air Place the liquid chamber in the cooling bath or
refrigerator in preparation for the next test (Warning—Do not
leave the vapor chamber with the gauge attached in the water bath for a longer period of time than necessary to condition for the next test Water vapor can condense in the Bourdon tube and lead to erroneous results.)
15.5.2 If the purging of the vapor chamber is done in a bath,
be sure to avoid small films of floating sample by keeping the bottom and top openings of the chamber closed as they pass through the water surface
15.5.3 Preparation of Gauge or Transducer—In the correct
operation of this procedure, liquid should not reach the gauge
or transducer If it is observed or suspected that liquid has reached the gauge, purge the gauge as described in12.5.3 The transducer has no cavity to trap liquid Ensure that no liquid is present in the T handle fitting or spiral tubing by forcing a stream of dry air through the tubing Connect the gauge or transducer to the vapor chamber with the liquid connection closed and place in the 37.8 °C (100 °F) bath to condition for the next test
PROCEDURE C FOR PETROLEUM PRODUCTS HAVING REID VAPOR PRESSURES ABOVE 180 kPa (26 psi)
16 Introduction
16.1 With products having vapor pressure over 180 kPa (26 psi) (seeNote 7), the procedure described in Sections8 –
12 is hazardous and inaccurate Consequently, the following sections define changes in apparatus and procedure for the determinations of vapor pressures above 180 kPa Except as specifically stated, all the requirements of Sections1 – 12shall apply
NOTE 7—If necessary, either Procedure A or B can be used to determine
if the vapor pressure of a product is above 180 kPa.
Trang 617 Apparatus
17.1 Apparatus as described inAnnex A1using the liquid
chamber with two openings
17.2 Pressure Gauge Calibration—A dead weight tester
(see A1.7) may be used as a pressure measuring device (see
A1.6) for checking gauge readings above 180 kPa (26 psi) In
7.1.1,9.1,12.4, and12.5.3where the words pressure
measur-ing device and pressure measurmeasur-ing device readmeasur-ing appear,
include as an alternative dead weight tester and calibrated
gauge reading, respectively.
18 Hazards
18.1 The precaution in7.1.6shall not apply
19 Sampling
19.1 Paragraphs8.3,8.3.1,8.4, and8.5shall not apply
19.2 Sample Container Size—The size of the sample
con-tainer from which the vapor pressure sample is taken shall not
be less than 0.5 L (1 pt) liquid capacity
20 Preparation for Test
20.1 Paragraphs11.1and11.2shall not apply
20.2 Any safe method of displacement of the test sample
from the sample container that ensures filling the liquid
chamber with a chilled, unweathered sample may be employed
Paragraphs 20.3 – 20.5describe displacement by self-induced
pressure
20.3 Maintain the sample container at a temperature
suffi-ciently high to maintain superatmospheric pressure but not
substantially over 37.8 °C (100 °F)
20.4 Completely immerse the liquid chamber, with both
valves open, in the water cooling bath for a sufficient length of
time to allow it to reach the bath temperature of 0 °C to 4.5 °C
(32 °F to 40 °F)
20.5 Connect a suitable ice-cooled coil to the outlet valve of
the sample container (see Note 8)
NOTE 8—A suitable ice-cooled coil can be prepared by immersing a
spiral of approximately 8 m (25 ft) of 6.35 mm (0.25 in.) copper tubing in
a bucket of ice water.
21 Procedure
21.1 Paragraphs12.1and12.2 shall not apply
21.2 Connect the 6.35 mm (0.25 in.) valve of the chilled
liquid chamber to the ice-cooled coil With the 12.7 mm
(0.5 in.) valve of the liquid chamber closed, open the outlet
valve of the sample container and the 6.35 mm (0.25 in.) valve
of the liquid chamber Open the liquid chamber 12.7 mm
(0.5 in.) valve slightly and allow the liquid chamber to fill
slowly Allow the sample to overflow until the overflow
volume is 200 mL or more Control this operation so that no
appreciable drop in pressure occurs at the liquid chamber
6.35 mm (0.25 in.) valve In the order named, close the liquid
chamber 12.7 mm (0.5 in.) and 6.35 mm (0.25 in.) valves; and
then close all other valves in the sample system Disconnect the
liquid chamber and the cooling coil (Warning—Combustible.
Keep away from heat, sparks, and open flame Keep container closed Use only with adequate ventilation Avoid prolonged breathing of vapor or spray mist Avoid prolonged, repeated
contact with skin.) (Warning—In addition to other
precautions, provide a safe means of disposal of liquid and vapor escaping during this whole operation.)
21.2.1 To avoid rupture because of the liquid-full condition
of the liquid chamber, the liquid chamber must be quickly attached to the vapor chamber and the 12.7 mm (0.5 in.) valve opened
21.3 Immediately attach the liquid chamber to the vapor chamber and open the liquid chamber 12.7 mm (0.5 in.) valve Not more than 25 s shall pass in completing the assembly of the apparatus after filling the liquid chamber, using the follow-ing sequence of operations:
21.3.1 Remove the vapor chamber from the water bath 21.3.2 Connect the vapor chamber to the liquid chamber 21.3.3 Open the liquid chamber 12.7 mm (0.5 in.) valve 21.4 If a dead weight tester is used as a pressure measuring device (see 17.2), apply the calibration factor in kilopascals (pounds-force per square inch) established for the pressure gauge to the uncorrected vapor pressure Record this value as the calibrated gauge reading and use in Section9in place of the pressure measuring device reading
PROCEDURE D FOR AVIATION GASOLINES APPROXIMATELY 50 kPa (7 psi) REID VAPOR
PRESSURE
22 Introduction
22.1 The following sections define changes in apparatus and procedure for the determination of the vapor pressure of aviation gasoline Except as specifically stated herein, all the requirements set forth in Sections 1 – 12shall apply
23 Apparatus
23.1 Ratio of Vapor and Liquid Chambers—The ratio of the
volume of the vapor chamber to the volume of the liquid chamber shall be between the limits of 3.95 and 4.05 (see A1.1.4)
24 Sampling
24.1 Refer to Section8
25 Preparation for Test
25.1 Checking the Pressure Gauge or Pressure Transducer—The gauge shall be checked at 50 kPa (7 psi)
against a calibrated pressure measuring device (see A1.6, A1.6.1, andA1.7) before each vapor pressure measurement to ensure that it conforms to the requirements of A1.2 This preliminary check shall be made in addition to the final gauge comparison specified in12.4or 15.4
26 Procedure
26.1 Refer to Section12
Trang 727 Keywords
27.1 crude oils; gasoline; Reid vapor pressure;
spark-ignition engine fuel; vapor pressure; volatility
ANNEXES (Mandatory Information) A1 APPARATUS FOR VAPOR PRESSURE TEST PROCEDURE A
A1.1 Reid Vapor Pressure Apparatus, consisting of two
chambers, a vapor chamber (upper section) and a liquid
chamber (lower section), shall conform to the following
requirements:
A1.1.1 Vapor Chamber— The upper section or chamber, as
shown in Fig A1.1, shall be a cylindrical vessel having the
inside dimensions of 51 mm 6 3 mm (2 in 6 1⁄8in.) in
diameter and 254 mm 6 3 mm (10 in.61⁄8in.) in length, with
the inner surfaces of the ends slightly sloped to provide
complete drainage from either end when held in a vertical
position On one end of the vapor chamber, a suitable gauge
coupling with an internal diameter of not less than 4.7 mm
(3⁄16in.) shall be provided to receive the 6.35 mm (1⁄4in.) gauge
connection In the other end of the vapor chamber, an opening
approximately 12.7 mm (1⁄2in.) in diameter shall be provided
for coupling with the liquid chamber Care shall be taken that the connections to the openings do not prevent the chamber from draining completely
A1.1.2 Liquid Chamber—One Opening—The lower section
or liquid chamber, as shown inFig A1.1, shall be a cylindrical vessel of the same inside diameter as the vapor chamber and of such a volume that the ratio of the volume of the vapor chamber to the volume of the liquid chamber shall be between 3.8 and 4.2 (seeA1.1.3) In one end of the liquid chamber an opening of approximately 12.7 mm (1⁄2in.) in diameter shall be provided for coupling with the vapor chamber The inner surface of the coupling end shall be sloped to provide complete drainage when inverted The other end of the chamber shall be
completely closed (Warning—To maintain the correct
vol-ume ratio between the vapor chamber and the liquid chamber,
DIMENSIONS OF VAPOR PRESSURE APPARATUS
A Vapor chamber, length 254 ± 3 10 ± 1 ⁄ 8
B, C, D Vapor and gasoline chambers,
Liquid ID
51 ± 3 2 ± 1 ⁄ 8
FIG A1.1 Vapor Pressure Apparatus
Trang 8paired chambers shall not be interchanged without
recalibra-tion to ascertain that the volume ratio is within the required
limits.)
A1.1.3 The ratio of paired vapor and liquid chambers to be
used for aviation gasoline testing shall be between 3.95 and
4.05
A1.1.4 Liquid Chamber—Two Openings—For sampling
from closed vessels, the liquid section of liquid chamber, as
shown inFig A1.1, shall be essentially the same as the liquid
chamber described inA1.1.2, except that a 6.35 mm (0.25 in.)
valve shall be attached near the bottom of the liquid chamber
and a 12.7 mm (0.5 in.) straight-through, full-opening valve
shall be introduced in the coupling between the chambers The
volume of the liquid chamber, including only the capacity
enclosed by the valves, shall fulfill the volume ratio
require-ments as set forth inA1.1.2
A1.1.5 In determining the capacities for the two-opening
liquid chamber (Fig A1.1), the capacity of the liquid chamber
shall be considered as that below the 12.7 mm (0.5 in.) valve
closure The volume above the 12.7 mm (0.5 in.) valve closure,
including the portion of the coupling permanently attached to
the liquid chamber, shall be considered as a part of the vapor
chamber capacity
A1.1.6 Method of Coupling Vapor and Liquid Chambers—
Any method of coupling the vapor and liquid chambers can be
employed, provided that no sample is lost from the liquid
chamber during the coupling operation, that no compression
effect is caused by the act of coupling, and that the assembly is
free of leaks under the conditions of the tests To avoid
displacement of sample during assembly, the male fitting of the
coupling must be on the liquid chamber To avoid compression
of air during assembly, a vent hole must be present to ensure
atmospheric pressure in the vapor chamber at the instant of
sealing (Warning—Some commercially available apparatus
do not make adequate provision for avoiding air compression
effects Before employing any apparatus, it shall be established
that the act of coupling the two chambers does not compress air
in the vapor chamber This can be accomplished by tightly
stoppering the liquid chamber and coupling the apparatus in the
normal manner, utilizing a 0 kPa to 35 kPa (0 psi to 5 psi)
gauge Any observable pressure increase on the gauge is an
indication that the apparatus does not adequately meet the
specifications of this test method If this problem is encountered, consult the manufacturer for a remedy.)
A1.1.7 Volumetric Capacity of Vapor and Liquid Chambers—To ascertain if the volume ratio of the chambers is
within the specified limits of 3.8 to5.2(seeA1.1.3), carefully measure a quantity of water greater than will be required to fill the two chambers (A dispensing buret is a convenient vessel for this operation.) Without spillage fill the liquid chamber completely The difference between the original volume and the remaining volume of the measured water quantity is the volume of the liquid chamber Without spillage couple the liquid and vapor chambers and fill the vapor chamber to the seat of the gauge connection with more of the measured water The difference between the final volume of the measured water quantity and the intermediate volume measured after ascertain-ing the liquid chamber volume is the volume of the vapor chamber
A1.2 Pressure Gauge—The pressure gauge shall be a
Bour-don type spring gauge of test gauge quality 100 mm to 150 mm (4.5 in to 6.5 in.) in diameter provided with a nominal 6.35 mm (0.25 in.) male thread connection with a passageway not less than 4.7 mm (3⁄16in.) in diameter from the Bourdon tube to the atmosphere The range and graduations of the pressure gauge shall be governed by the vapor pressure of the sample being tested, in accordance with Table A1.1 Only accurate gauges shall be continued in use When the gauge reading differs from the pressure measuring device reading, or dead-weight tester reading when testing gauges above 180 kPa (26 psi), by more than 1 % of the scale range of the gauge, the gauge shall be considered inaccurate For example, the cali-bration correction shall not be greater than 0.3 kPa (0.15 psi) for a 0 kPa to 30 kPa (0 psi to 15 psi) gauge or 0.9 kPa (0.3 psi) for a 0 kPa to 90 kPa (0 psi to 30 psi) gauge
NOTE A1.1—Gauges 90 mm (3.5 in.) in diameter can be used in the 0 kPa to 35 kPa (0 psi to 5 psi) range.
A1.3 Cooling Bath—A cooling bath shall be provided of
such dimensions that the sample containers and the liquid chambers can be completely immersed Means for maintaining the bath at a temperature between 0 °C and 1 °C (32 °F and 34
°F) must be provided Do not use solid carbon dioxide to cool
TABLE A1.1 Pressure Gauge Range and Graduations
Reid Vapor Pressure
Gauge to be Used Scale Range
Maximum Numbered Intervals
Maximum Intermediate Graduations
Trang 9samples in storage or in the preparation of the air saturation
step Carbon dioxide is appreciably soluble in gasoline and its
use has been found to be the cause of erroneous vapor pressure
data
A1.4 Water Bath—The water bath shall be of such
dimen-sions that the vapor pressure apparatus can be immersed to at
least 25.4 mm (1 in.) above the top of the vapor chamber
Means for maintaining the bath at a constant temperature of
37.8 °C 6 0.1 °C (100 °F 6 0.2 °F) shall be provided In order
to check this temperature, the bath thermometer shall be
immersed to the 37 °C (98 °F) mark throughout the vapor
pressure determination
A1.5 Thermometer —An ASTM Reid Vapor Pressure
Ther-mometer 18C (18F) having a range from 34 °C to 42 °C (94 °F
to 108 °F) and conforming to the requirements in Specification
E1 Alternative non-mercury-containing liquid-in-glass
ther-mometers such as thermometer S18C in Specification E2251
conforming to the temperature range with equal or better
accuracy may be used
A1.6 Pressure Measuring Device—A pressure measuring
device having a range suitable for checking the pressure gauge
employed shall be used The pressure measuring device shall
have a minimum accuracy of 0.5 kPa (0.07 psi) with
incre-ments no larger than 0.5 kPa (0.07 psi)
A1.6.1 When a mercury manometer is not used as the
pressure measuring device, the calibration of the pressure
measuring device employed shall be periodically checked
(with traceability to a nationally recognized standard) to ensure that the device remains within the required accuracy specified
inA1.6
A1.7 Dead-Weight Tester—A dead weight tester may be
used as the pressure measuring device (A1.6) for checking gauge readings above 180 kPa (26 psi)
A1.8 Sample Transfer Connection—This is a device for
removing liquid from the sample container without interfering with the vapor space The device consists of two tubes inserted into a two-holed stopper of appropriate dimensions to fit the opening of the sample container One of the tubes is short for the delivery of the sample, and the other is long enough to reach the bottom corner of the sample container Fig A1.2 shows a suitable arrangement
A2 APPARATUS FOR VAPOR PRESSURE TEST PROCEDURE B
A2.1 Vapor Pressure Apparatus—Refer toA1.1.1 through
A1.1.7
A2.2 Pressure Gauge—The pressure measuring system
shall be a Bourdon type spring gauge, as described inA1.2or
a suitable pressure transducer and digital readout The pressure
measuring system shall be remotely mounted from the vapor
pressure apparatus and terminations provided for use of a quick
connection type fitting
A2.3 Cooling Bath—(Warning—To maintain the correct
volume ratio between the vapor chamber and the liquid
chamber, paired chambers shall not be interchanged without
recalibration to ascertain that the volume ratio is within the
required limits.)
A2.4 Water Bath—The water bath shall be of such
dimen-sions that the vapor pressure apparatus can be immersed in a
horizontal position Provision shall be made to rotate the
apparatus on its axis 350° in one direction and then 350° in the
opposite direction in repetitive fashion Means for maintaining
the bath at a constant temperature of 37.8 °C 6 0.1 °C (100 °F
60.2 °F) shall be provided In order to check this temperature, the bath thermometer shall be immersed to the 37 °C (98 °F) mark throughout the vapor pressure determination A suitable bath is shown in Fig A2.1and is available commercially
A2.5 Thermometers—Refer toA1.5
A2.6 Pressure Measuring Device—Refer toA1.6
A2.7 Flexible Coupler—A suitable flexible coupling shall
be provided for connection of the rotating vapor pressure apparatus to the pressure measuring device
A2.8 Vapor Chamber Tube—The vapor chamber tube of
inner diameter 3 mm (1⁄8 in.) and length of 114 mm (4.5 in.) shall be inserted into the pressure measuring end of the vapor chamber to prevent liquid from entering the vapor pressure measuring connections (seeFig A2.2)
A2.9 Sample Transfer Connection—Refer toA1.8
FIG A1.2 Sample Transfer Connection
Trang 10SUMMARY OF CHANGES
Subcommittee D02.08 has identified the location of selected changes to this standard since the last issue (D323 – 15) that may impact the use of this standard (Approved June 1, 2015.)
(1) Deleted former 3.1.3, definition for gasoline-oxygenate
blend.
Subcommittee D02.08 has identified the location of selected changes to this standard since the last issue (D323 – 08 (2014)) that may impact the use of this standard (Approved April 1, 2015.)
(1) Revised Referenced Documents to add Specification
E2251
(2) Revised A1.5
FIG A2.1 Apparatus for Vapor Pressure, Procedure B
FIG A2.2 Vapor Chamber Tube Inserted in Vapor Chamber